1. Field of the Invention
The present invention relates to a gardening tool and, more particularly, to a pruning shears to shear a plant at a higher position.
2. Description of the Related Art
A conventional pruning shears in accordance with the prior art shown in FIG. 6 comprises a shank 40, a cutting unit 50, a threaded rod 62 and a locking knob 60. The shank 40 has an upper end provided with a fixed seat 42, a first toothed portion 422 and a second toothed portion 423. The fixed seat 42 of the shank 40 has an inner portion provided with a shaft hole 421. A pulley 41 is mounted on a side of the shank 40. The cutting unit 50 includes a pivot seat 53 pivotally mounted on the fixed seat 42 of the shank 40, a fixed blade 51 mounted on the pivot seat 53, a movable blade 512 pivotally connected with the fixed blade 51, a drive member 52 connected with the movable blade 512 to drive the movable blade 512 to move relative to the fixed blade 51, an elastic member 521 biased between a side 511 of the fixed blade 51 and the drive member 52, and a drive cord (not shown) passing through the pulley 41 and connected with the drive member 52 to drive the drive member 52. The pivot seat 53 of the cutting unit 50 has an inner portion provided with a pivot hole 533 to receive the fixed seat 42 of the shank 40. The pivot seat 53 of the cutting unit 50 has a first side provided with a first serrated portion 531 engaging the first toothed portion 422 of the shank 40 and a second serrated portion 532 engaging the second toothed portion 423 of the shank 40. The pivot seat 53 of the cutting unit 50 has a second side provided with two spaced positioning pieces 534. The threaded rod 62 has a first end extending through the pivot hole 533 of the pivot seat 53 and the shaft hole 421 of the fixed seat 42 and a second end provided with an enlarged positioning plate 621 positioned between the two positioning pieces 534 of the pivot seat 53. The locking knob 60 is mounted on the fixed seat 42 of the shank 40 and has an inner portion provided with a screw bore 61 screwed onto the threaded rod 62 to clamp the fixed seat 42 of the shank 40 and the pivot seat 53 of the cutting unit 50 between the locking knob 60 and the positioning plate 621 of the threaded rod 62.
In operation, the drive cord is driven by a control handle to move the drive member 52 which drives the movable blade 512 to move relative to the fixed blade 51 so as to perform a cutting action. In adjustment, when the locking knob 60 is rotated relative to the fixed seat 42 of the shank 40 to unscrew the screw bore 61 from the threaded rod 62, the first serrated portion 531 of the pivot seat 53 disengages the first toothed portion 422 of the shank 40, and the second serrated portion 532 of the pivot seat 53 disengages the second toothed portion 423 of the shank 40, so that the pivot seat 53 is pivoted relative to the fixed seat 42 so as to adjust the angle of the cutting unit 50. However, the pivot seat 53 is pivoted relative to the fixed seat 42 in a straight direction so that the angle of the cutting unit 50 is adjusted in a one-dimensional manner, thereby limiting the cutting direction of the cutting unit 50.